The invention belongs to the acceleration engineering, especially to the linear induction accelerators of charged particles and might be used as a commercial-type compact accelerator for the formation of singular and multiple parallel relativistic beams, including beams of different energy and charge signs.
There is known a devise (electrostatic accelerator-EA), which is able to work as an accelerator of charged particles (Cockcroft J. D., Walter E. T. C. xe2x80x9cExperiments with high velocity ions. Further developments in the method of obtaining high velocity positive ions.xe2x80x9d Proc. Roy. Soc. A, vol. 136, p 619, 1932.) The devise is composed of an injector block, acceleration block, drive source, and output devise. The basic shortcomings of EA are excessive dimensions, high cost, high operational danger and low beam (or beams) current of accelerated charged particles. All the mentioned shortcomings are caused by the structural peculiarity of drive source, having components under hundreds of thousands to million (and in many cases higher than that) volts. High-pressure (from 5 to 30 atmosphere) gases and special electro-technical oils are used for securing the isolation of these components. This makes the operation of such accelerators dangerous and makes impossible to fabricate small-dimension and simultaneously powerful accelerating systems. The mentioned above shortcomings are the basic hindrance for the formation of the compact, inexpensive, and safe in operation commercial-type devises (accelerators) for generation of the singular and multiple parallel beams of charged particles, including such that have beams of different energy and of different charge sign. These shortcomings become especially substantial at work with  greater than 1 MeV electron beams.
A linear induction accelerator, which can work as a compact devise for formation of singular relativistic beams of charged particles is also known (Redinato L. xe2x80x9cthe advanced test accelerator (ATA), a 50 MeV, 10 kA Inductional Linacxe2x80x9d, IEEE Trans., NS-30, No.4 pp. 2970-2973, 1983). This devise is known also as single-channel linear induction accelerator (SLIA). Like the EA accelerator, SLIA contains injector block, accelerator block, drive source and output device. Its peculiarity is in that the accelerating block has the form of an inductor with one working channel for acceleration of charged particles. The acceleration of charged particles in SLIA is achieved by the effect of the longitudinal vortex electric field, having relatively low frequency (tens MHz), which is generated in the working channel of the inductor by special windings, having changing in time current. The inductor contains cores, made of high-frequencies magnetic materials with an elevated electric strength, made of ferrites, amorphous magnetic materials, etc. Because of this, SLIA does not have the shortcoming of the EA, which requires super-high potential difference in construction of elements of the working (accelerating) channel. This makes SLIA more operation safe. In contrast to EA, much more strong (including many amper and also kiloamper) beams of charged particles can be accelerated in SLIA.
The basic shortcoming of SLIA is, that during its performance, a strong external vortex electric field can be generated in its surrounding. (In contrast to the external, a vortex electric field in the acceleration (working channel is classified as the internal field; in contemporary SLIA, the potential of the internal field might reach tens MV/m). In uncommon situations, or in a case of improper operation, the external vortex electric field may be dangerous for the operating personnel as well as for the surrounding apparatuses when they are not properly screened. In other words, SLIA has a low level of electromagnetic compatibility. The other side of the problem of the electromagnetic compatibility consists of that the presence of the presence of a strong external field leads to the formation of a peculiar xe2x80x9cdead zonexe2x80x9d, work in which demands special means of protection. This limits the possibility of using the space directly surrounding the accelerating block of SLIA. The latter can be considered that the real dimensions, e.g. transversal dimensions, of SLIA might be significantly larger than the transversal dimensions of the accelerating block. The dimensions of the space surrounding SLIA beyond which the intensity of the external vortex electric field decreases to some accepted value is called the working dimension of SLIA. It is clear; the higher is the intensity of the internal electric field in the accelerating channel the larger is the working dimension of the system. Consequently, a principal contradiction exists in the structural concept of SLIA between the effort to increase the tempo of the acceleration by the way of an increase of the internal vortex electric field and the simultaneous increase of the working dimension of the system.
The use of especial metallic screens is the basic technologic solution, which secures a decrease of the external electric field in SLIA. The weakening of the external field is achieved by the organization of the additional field-energy losses in the volume of the screen.
A radical decrease of the strength of the external electric field by this method was practically not achieved. In some structures the metallic screens serve also as the elements of the conducting circuit, used to form a difference in voltage in the acceleration space (Pasour J. A., Lucey R. F., Robertson C. W. Long pulse free electron laser driven by a linear induction accelerator, Proc. SPIE, v. 453, pp. 328-331, 1984).
In addition to the above, the energy, which is used for generating the external electric field in SLIA, is comparable to the energy used for the generation of the internal field in the working channel. It means, that the efficiency coefficient of SLIA cannot be high. This is also one of the basic shortcomings of this class of structures.
The large real (working) dimensions and the necessity to apply safety measures result in high price of fabrication and of operation of SLIA. This leads to the conclusion that use of SLIA, as the key construction element, for various type commercial application devises is unsuitable. Besides this, the above-described characteristics of SLIA are incompatible with the traditional technologic culture, which is typical in civil (common) industry, e.g. light, food, pharmaceutical industry, inc.
Consequently, the presence of a strong external vortex electric field (and related with it the low electromagnetic compatibility and large energy losses) is the basic factor causing the basic shortcomings of SLIA. It causes an elevated danger in operation, large working dimensions, and complexity of construction, low efficiency coefficient, expensive manufacturing and technologic incompatibility with the typical conditions present in civil industry.
The functional limitation is the other essential shortcoming of SLIA. Each separately taken SLIA cannot be used for an independent simultaneous acceleration of a few beams of charged particles, including such which differ in charge sign of particles.
The given devise is the most similar in technical essence and in the obtained results to the proposed invention and is considered as the prototype of the invention.
The aim of the invention is to create a commercial-type linear induction accelerator, which has wider functional abilities (for instance, the ability to accelerate simultaneously a few beams of charged particles, including particles having different charge sign), realistic compatibility, high degree of electromagnetic compatibility and efficiency coefficient, operational safety, low manufacturing cost, simple structure, and high technology (it means, a technology which is adequate to the typical conditions in the civil industry). This is achieved by improving the structure of the inductor of the accelerator block this allows to decrease drastically the strength of the external electric field. The proposed invention is called the multi-channel induction accelerator (MLIA).
The arising task is solved as follows: according to the invention, in the multi-channel induction accelerator (which encompasses an injector block, accelerating block, drive source, and output devices for the linear beams of charged particles) the accelerating block has a form of at least two electrodynamically linked blocks of one-channel linear induction accelerators, or one-channel accelerating blocks, which have output devices for linear beams of charged particles attached to the output of the linked accelerating block. They are oriented in such way that the electric-field direction of the working channel of each of the one-channel accelerating block is opposed to the direction of the field of at least one of the neighboring one-channel accelerating blocks.
The arising task is solved as follows: according to the invention, in the multi-channel induction accelerator (which encompasses an injector block, accelerating block, drive source, and output devices for the linear beams of charged particles) the accelerating block has a form of at least two electrodynamically linked blocks of one-channel linear induction accelerators, or one-channel accelerating blocks, which have output devices for linear beams of charged particles attached to the output of the linked accelerating block. They are oriented in such way that the electric-field direction of the working channel of each of the one-channel accelerating block is opposed to the direction of the field of at least one of the neighboring one-channel accelerating blocks.
In addition to this, four structural variants are proposed for linking of the accelerating blocks with the injection block:
In the first variant, the injection block has a form of one injector of charged-particle beams which is attached to one of the accelerating blocks in such way that electric field in the working channel is accelerating for the charged particles of the injector, which is attached to it and oriented in opposite direction to the field direction in all the remaining neighboring with this block one-channel linear induction accelerators.
In the second variant, the injection block has is made in a form of a system of the same sign charged-particles injectors attached to a part of the one-channel accelerating blocks from one and the same side. Beside this, all the one-channel acceleration blocks are attached to injectors in the way that the electric field in each of the one-channel accelerating blocks is accelerating for the charged particles of the injector, which is attached to them.
In the third variant, the injection block has a form of two smaller injection blocks of beams of the same-charge particles, each of them is placed facing the opposite ends of the working channels of the one-channel accelerating blocks. The injectors are attached to the working channels in such way that the electric field in each of the one-channel accelerating block is accelerating for the charged particles of the injector, which is attached to it.
In the fourth variant, the block of injectors is made of two smaller blocks, each of which is a sub-block of injection of different-sign charged-particle beam. These injectors are attached, from one and the side, to the one-channel accelerating blocks. Each of the one-channel accelerating block, which has an injector attached to it, has the acceleration direction in the working channel of the type of the charged particles which are generated by the attached injector.
Besides this, in each of the four variants, four variants of mutual orientation are proposed for the accelerating blocks of the one-channel linear induction accelerators.
In the first case of the mutual orientation, the accelerating block is made in such way that the axis of the working channels of the one-channel linear induction accelerators are parallel; it means they do not cross.
In the second case, the accelerating block is built in the way that the axis of the working channels of the accelerating blocks of the one-channel linear induction accelerators are not parallel and are crossing in one point.
In the third case, the accelerating block is built in such way that the axis of the working channel of the acceleration blocks of the one-channel linear induction accelerators are not parallel and do not cross.
In the fourth case, the acceleration block is built in such way that the axis of the working channels of the accelerating blocks of the one-channel linear induction accelerators are not parallel and have different axis crossing in various places.
Building of the multi-channel linear induction accelerator of charged particles, totally with all the essential characteristics, including above described different structural variants of the accelerator block as well of the schemes in forming of this block with the injector block, allows to realize a situation when the external vortex electric fields of all one-channel linear induction accelerators, beyond the limits of their working channels mutually cancel each other (it means, they are of the opposite signs), when within the volume of the working channel of the one-channel linear induction accelerators they are of the sign. Consequently, the external electric field of the MLIA decreases drastically as function of distance from the MLIA external surface. Because of it, their operation becomes markedly more safe, the working dimensions decrease (the dimensions of the xe2x80x9cdead zonexe2x80x9d decrease), the real dimensions of the accelerator decrease, the structure is simplified, and this opens the possibility of the accelerator""s commercial application in the conditions, typical to the civil industry conditions.
Patent search for devises with the similar characteristics were not detected and also the information was not found (by the search) about the effects, foreseen by the essential evidence of the invention for obtaining the described technical result. This allows concluding that the declaration of the technical solution corresponds to the criterion of patentable xe2x80x9cnoveltyxe2x80x9d and to the xe2x80x9cinvention level.xe2x80x9d